Control for superchargers



CONTROL FOR 5U PERCHARGERS Filed Feb. 1'7, 1939 2 Sheets-Sheet 1 Fly. 4

INVENTOR 3+ Fol/A mmanh/ 1 Q Q. 44. 4 W

ATTORNE Jan. 14, 1941. R. AMMANN 2,228,239

. CONTROL FOR SUPERCHARGERS Filed Feb. 17, 1939 2 Sheets-Sheet 2 ME TOR flolfflmmann EYJ Patented Jan. 14,1941

CONTROL FOB SUPEROHARGERS Rolf AmmannrMunich, Germany, assignor to Bayerlache Motoren Werke Aktiengesellschait, Munich, Germany, a company of Germany Application February 17,1939, Serial No. 256,886 In Germany June 9, 1937 6 Claims.

This invention relates to'an improved control for superchargers, and more particularly to a correlated throttle valve and .speed control system for the same.

An object of this invention is to provide an improved supercharger control arrangement particularly adapted for use with aircraft engines.

A further object of this invention is to provide an improved control arrangement for properly correlating the action of a supercharger throttle valve and the supercharger speed control gearing. I

An additional object of this invention is to provide an arrangement for interconnecting the throttle valve and speed change control of a supercharger in such a manner that undesired speed changes in response to control movement of the throttle valve are avoided.

These and other features, capabilities and advantages of the invention will appear from the subjoined detailed description 01 one embodiment and modification thereof, illustrated in the accompanying drawings, in which:

Fig. 1 is a partially schematic view illustrating a preferred control arrangement for the throttle valve and transmission of an engine supercharger; and

Fig. 2 illustrates a modified linkage-system interconnecting the throttle valve and supercharger drive. i

In the preferred arrangement illustrated in Fig. 1, a throttle valve 1, inthe form of a butterfly valve, is controlled by a pressure-responsive device generally indicated at 2 and a hand lever 3 for varying the amount, of air supplied to the supercharger 4. Assuming that the supercharger- 4 supplies air to an aeroplane engine, the hand lever 3 is positioned adjacent the operator or the aeroplane for varying 'at will the position of the throttle valve I and/or thesetting oi the pressure-responsive device 2. The latter is preferably interconnected by a suitable conduit 5 with the discharge side of the supercharger 4, whereby a variation in the discharge pressure, which, in turn, will varywith the altitude of the aeroplane, acts upon the pressure-responsive device. The pressure-responsive element itself may take the form of a metal bellows 8 actuating a control I, which, depending upon the expansion or contraction of the bellows I will force oil under pressure to one side or the other of the piston I. Movement of the pistbn 8 is transmitted to the throttle valve I through suitable links I. lis previously stated, the hand lever I may be used to directly move the throttle valve I, as by direct connection with one of the links I, and also necting two-arm lever II.

- termediate its ends about a fixed point. other end of the double-arm lever II is then suit- Atw/o-speed drive, generally indicated at II is used to interconnect the supercharger I with the aeroplane engine (not shown). In the preferred form of this invention, illustrated in Fi 1, the linkage system for controlling the transmission II vfrom the throttle valve I preferably consists,

as shown, of a first double-arm lever I2, pivoted intermediate its end about a fixed point, a link I3 pivotally interconnecting one end of this first double-arm lever I2 with one end of a second double-arm lever II also'pivotally mounted in- The ably interconnected with the throttle valve I through links I5. The other end I5 ofv the double-arm lever I2 is preferably interconnected through a tension spring I1 with one end of an arm II pivoted suitably about fixed point l9. Actual switching of the transmission from one step to the'other is accomplished through a link 20 which is pivotally interconnected to the free end of the arm I8 and actuates a gear control lever 2|. By a suitable dimensioning and arrangement of this linkage system, as has been shown in Fig. 1, it will be seen that intermediate the end positions of the valve I, that is, intermediate the full open and full closed positions, the valve I together with link I5, double-arm lever I4, link I3, anddouble-arm lever I2 may move relatively freely, being affected solely by the spring II which will act as substantially a fixed point for the arms 20 and 2| of the transmission. However, assuming that the valve I reaches its full open position, indicated by the dashed lines, the

end II of the double-arm lever I2 will have movedto the other side of the pivot point I9, acting as a dead center, and the spring II will quicklyassume substantially the same relative position on the other side of the point I I9. Through the links 20 and 2| such movement of the spring and the free end of the arm I8 will effectively instantaneously shift the transmission I I to the other step.

Considering the control system in its entirety, it can be assumed that when the aeroplane is on the ground or at low altitudes, the transmission I I I will be in such a position as to drive the supercharger at a relatively slow speed, while the valve I will be more or less closed depending upon the initial setting predetermined by the operator through the' control lever 3. As the aeroplane rises to higher altitudes the pressure-responsive device will move the valve I to supply more 'and more air to the supercharger I. When substantially lull opening of the valve I, has been reached, the pivot point II on the end of the double arm lever II will move beyond the dead-center point II, and thus the spring I! and arm II .will snap to a new position on the opposite side oi.

the dead-center point l9, thereby actuating link and control lever 2| to move the transmission H to a higher speed for the supercharger 5. In-' creased air wili then be supplied to the'engine, although the air supply to the supercharger 4 itself will immediately become 'throttled to some degree through movement of the pressure-rethe arrangement will work in an identically op- 'posite sequential manner, as will be obvious to those skilled in sion.

In the modification. illustrated in Fig. 2, the necessary lost motion between the double-arm lever I2 and the transmission controls 20, 2| is eifected by an alternative arrangement. In this case, a slotted guide 22 is provided on the free end of a link 23 pivoted to the lower end of the double-arm lever l2. About a substantially fixed point 24 there is pivoted intermediate its end another double-arm lever 25 provided at one end with a pin 28 engaging the slotted guide 22, and at its other end pivotally interconnected to: the link 20 actuating the transmission control lever 2|. It will be seen that'this arrangement works in a manner similar to that previously described and illustrated in Fig. 1. A certain amount of movement 01' the double-arm lever l2, resulting from intermediate movement oi! the valve I, will be permitted, since the slotted guide 22 will merely slide on the pin 26. When, however, the valve i reaches its end position, the double-arm lever l2 will have moved to such a degree that the end of the slotted guide 22, coming into contact with the pin 26 will rotate the double arm lever 25 to a position in which the transmission, through link 20 and control lever 2| will have been moved to another driving step.- In the new this art without further discusposition, indicated by the dashed line in Fig. 2,

the throttle valve may be closed to some degree without reversely moving the gear of the supercharger drive. Upon descent of the aeroplane, however, a reverse shiitingof the supercharger drive will take place-as the pin 26 will then be moved by the opposite end of the slotted guide 22.

It will be obvious to those skilled in this art that other variations and modifications oi the aioredescribed arrangement may take place, all within the scope oi the-presentinvention. For example, the specific type of pressure-responsive device illustrated is of no particular importance, and any proper device, some of which are well 1 known in the art, may be used to initiate the control. Additionally, it desired, the pressure-responsive actuating device may be responsiveto atmospheric pressure directly. if so desired. While the control of the speed-change drive I I has been indicated as a direct one, the interconnecting link 20 might easily act upon suitable indirect gear shifting mechanism of the type well known to the art. Additionally, while the linkage system or shifting the speed-change drive has been illustrated as directly interconnected with the valve I, it will also be obvious that it might, with substantially the same results, be directly connected to the pressure-responsive device. In this case, the linkage mechanism is so arranged that in case 01' complete opening of the pressureresponsive regulator the switching from the low er to the higher steps will take place, and upon. complete closing, switching back from the higher to the lower step will follow.

I claim:

1. In an arrangement adapted for use with an trol lever for changing the transmission from 2 one to the other speed only when said throttle valve reaches substantially treme positions. 2. The combination according to claim 1, in combination with manual means for actuating said throttle valve and controlling the intial set 01. said pressure-responsive means.

3. The combination according to claim'l, in which the means interconnecting said throttle valve and said control lever includes a lost-motion device for permitting movement of said throttle valve between its extreme positions without initiating actuation of said transmission.

. 4. The combination according to claim 1, in which the means interconnecting said throttle valve and said control lever include means for urging said transmission to one'or the other speed while permitting movement of said throttle valve intermediate its extreme control positions.

5. The combination according to claim 1, in which the means interconnecting said throttle valv and said control lever include an arm pivotally fixed at one end, a control rod connected at one end to said control lever and pivotally connected at its other end to the other end of said arm, a double-arm lever. pivotally fixed intermediate its ends, a linkage pivotally interconnecting one end of said double-arm lever to said throttle valve, and a spring interconnecting the other end of said double-arm lever with the other end of said arm.

6. The combination according to claim 1, in which the means interconnecting said throttle valve and said controllever includes a pair of double-arm levers pivotally'fixed intermediate their ends, a first control link pivotally interconnecting one end of one of said arms to said controllever, a second control linkage pivotally interconnecting one end of the other of said double-arm levers to said throttle valve, and a cone necting rod pivotally connected at one end to the other end of the other of said double arm levers and provided with a slotted guide engaging the other end of said one double-arm lever.

ROLF AMMIANN.

either one oi its ex- 

